title: Theoretical and experimental studies on isotachophoresis in multi-moving chelation boundary system formed with metal ions and EDTA.
abstract: In this paper, a general mode and theory of moving chelation boundary based isotachophoresis (MCB-based ITP), together with the concept of decisive metal ion (DMI) having the maximum complexation constant (lg Kmax) with the chelator, were developed from a multi-MCB (mMCB) system. The theoretical deductions were: (i) the reaction boundary velocities in the mMCB system at steady state were equal to each other, resulting in a novel MCB-based ITP separation of metal ions; (ii) the boundary directions and velocities in the system were controlled by the fluxes of chelator and DMI, rather than other metal ions; and (iii) a controllable stacking of metal ions could be simultaneously achieved in the developed system. To demonstrate the deductions, a series of experiments were conducted by using model chelator of EDTA and metal ions of Cu(II) and Co(II) due to characteristic colors of blue [Cu-EDTA](2-) and pink [Co-EDTA](2-) complexes. The experiments demonstrated the correctness of theoretical deductions, indicating the validity of the developed model and theory of ITP. These findings provide guidance for the development of MRB-based ITP separation and stacking of metal ions in biological sample matrix and heavy metal ions in environmental samples.
authors.affiliation: Laboratory of Bioseparation and Analytical Biochemistry, State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Chen-Gang
authors.initials: CG
authors.lastname: Guo
authors.forename: Liu-Yin
authors.initials: LY
authors.lastname: Fan
authors.forename: Cheng-Xi
authors.initials: CX
authors.lastname: Cao
mesh_terms: D002021:Buffers; D002614:Chelating Agents / Q000737:chemistry*; D003035:Cobalt / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry*; D057625:Isotachophoresis / Q000379:methods*; D008962:Models, Theoretical; D009038:Motion; D013056:Spectrophotometry, Ultraviolet
chemical_list: D002021:Buffers; D002614:Chelating Agents; D003035:Cobalt; D003300:Copper; D004492:Edetic Acid